actually I showed some bad examples..... You are allowed to take a step further. Allthough with some restrictions I guess. If someone threatens you, you are not allowed to punch them. But say if someone starts a fight with you. Then you are of course allowed to put a stop to the fight. But you are not alloed to apply more force then what is necessary.
This is not a law, but more of a guideline. The same guidelines apply to both police and the common man.
The goal here is to prevent unecesary violence, as in this case where he shot them in the back.

Of course you are right with that the burglar also violates your privacy. But does this give you the right to take someones life?
Could you consider to withstand some of your privacy to SAVE someones life?

if so, then I think you can be able to NOT shoot the assailant and let the police do their work. They are qualified in dealing with agressors in a safe and humane way.